IOS 6.1 update and Siri

I can't say I'm a Siri "pro" but I use it occasionally and most of that is in my car for finding and dialling numbers, via BT. After updating my IP5 the other day, with 6.1, Siri just seems to hang and be non-repsonsive in my car - but works OK outside the car.

Also, I'm not even sure that Siri was updated this time - but it has definitely changed.
Perhaps the BT was upgraded/changed? Can anyone confirm?

Is it just me or are there some others that are also having trouble since the update?: